Piston



Patented Oct. 16, 1928.

AUNITED STATES PATENT OFFICE.

`arrondi: WENTWETH-GEAYSON, E SYDNEY, NEW SoUTII WALES, AUSTRALIA, As-

srairoia;- ToioEAYsoN ENGINE COMPANY LIMITED, or SYDNEY, NEW soUTIIWALES,

-"tues tothefcooling of the na 'combustion engines by Vthe through;

internal combustion engines--topass atmosphericair'or air from a receiier` across tlie Vspace `formed between the underside of the piston andan extension thereof which acts as a guide t0 which the gudgeon pin issecured. Further, a two stroke cycle internal combustion engine having astepped piston has been proposed 1n which air is drawn into and expelledfrom the space formed between the larger diameter of the cylinder andthe smaller diameter of the piston during its outward and inwardstrokes.

The present invention consists in an internal combustion engine having astepped cylinder, in which the stepped piston is formed as a doublehollow casing that connects the space by means of a valve or valves withthe crank chamber by which the induction air is passed to cool'thepiston.

The invention is further characterized by the provision of an internaldividing wal transverse fins above the said wall, and by ports in thewall of the piston on one slde of the dividing wall and valves in thebase of the piston on the other side thereof.

The invention will now be described with reference to the accompanyingdrawin which illustrate a piston constructed accor ing to the inventionand applied to an internal combustion engine operating on the two cycleprinciple.

Figure 1 is a sectional elevation of the piston and part of thecylinder,

Figure 2 is a section at right angles to that shown in Figure 1,

Figure 3 is a sectional perspective view of the piston on the planeshown in Figure 1,

Figure 4 is a sectional perspective view of thei piston on the planeshown in Figure 2, an

Figure 5' is a sectional perspective view of the lower part of thepiston.

The tandem stepped cylinder 6 and crankcase 7 are of well knownconstruction and design and have the usual scavenging and combustion airpassage 8 and ports 9 exhaust ports 10 and water jacket 11.

The piston '12 is stepped and hollow and is provided with a central airtight pocket 13 coMrANY oF NEW SOUTH WALES. AUSTRALIA.

' PISToN.

sts, 1926, Serial No. 126,829` andl in Australia August 28, 1925.

for the reception of the connecting rod 14 and its little end 15, inwhich the gudgeon pin 16 and any well known s stem of brasses anddistance pieces are fitte The piston is also rovided with a centraldividing wall 17 an at right angles to this a number of parallel coolingfins 18 and on one side of the wall 17 near its lower end a number ofinlet ports 19. On the other side of the wall 17 and in its base it hasa pair of valves 20 of any well known automatic type. The induction airis admitted through ports 21 in the enlarged part of the cylinder whichare so situated that when the piston is at the top of its stroke theyare uncovered by the lower flange 22.

The course of the incomin air when the piston is moving upwards t uscreating a partial vacuum in the crankcase is as follows l Through theinlet ports 21 to the space 23 and through the ports 19 to the interiorof the piston on one side of the wall 17 and then upwards past the ns 18and down the interior of the piston on the other side of the wall 17 tothe crankcase 7 through the valves the ports 21 become uncovered and airis admitted direct to the crankcase.

On the return stroke of the piston, the valves 20 close and the air iscompressed in the crankcase and afterwards admitted to the cylinder 6 inthe usual manner when the port 9 becomes uncovered.

When the iston is used in an engine working on the our cycle principlethe heated air from the crankcase may be led to the cylinder airinduction pipes, suitable and well known non-return valves being placedtherein and, if required, at the entrance to the ports 21. l

In four cycle engines the ow of the airv ma)7 be reversed by reversingthe direction of openingof the valves 20, putting a check valve on theair opening to the crankcase and taking the heated air from the ports 21to the induction pipe.

The construction may also be applied to air compressors for the purposeof cooling the piston.

I claim:

1. In an internal combustion engine, a

let valves in the base of the piston on the other side of said wall andair inlet ports' in the enlarged part of said stepped cylinder. 2. In aninternal combustion engine, a

- stepped cylinder, a stepped hollow piston' therein, a pocket in saidpiston for receivin the connecting rod of the engine, a centra internaldivdmg wall in said piston, transverse ns above said wall, inlet orts inthe wall of the piston on one side o4 said dividing wall, outlet valvesin the base of said l5 piston on the other side of said divi wall andinlet ports in the enlarged part o said cylinder.

3. In an internal combustion engine, a stepped cylinder, a step formedas a double hollow caslng, the space of which communicates with thecrank chamber of the engine, and valves in said piston for controllingthefpassage of induction air through the space so as to cool the iston.25

In testimony whereofI have a ed my signature. t GEGRGE WENTWORTHGRAYSON.

pedu piston therein 20

